Adapted from williams-sonoma.com
lb. Yukon Gold potatoes, peeled and quartered
lb. celery root, peeled and cut into ½-inch pieces
Tbs. (½ stick) unsalted butter
cup heavy cream
Salt and freshly ground pepper, to taste
Put the potatoes, celery root and water in an electric pressure cooker. Cover and cook for 6 minutes according to the manufacturer¿s instructions. Release the pressure according to the manufacturer¿s instructions. Drain the potatoes and celery root. Meanwhile, in a small saucepan over medium heat, combine the butter and cream. Heat until the butter melts and small bubbles form around the edges of the pan. Reduce the heat to low and keep warm. Set a food mill over a large bowl and puree the vegetables in batches. Using a spatula, stir in the cream mixture in two additions, allowing each addition to be absorbed before adding more. Season with salt and pepper and serve immediately.